Optical encoding

ABSTRACT

An article includes at least one surface with a visual feature included thereon and a plurality of elements with at least a portion of the elements being of selected optical states in accordance with a predetermined code, so that the visual feature is encoded with information. The article further includes a security feature which incorporates a security code with the security feature being formed so that the security code is random, and with the information encoded into the visual feature of the article including a code derived from the security feature and corresponding to the security code.

The present invention relates to a substrate or other article having asurface provided with an alpha-numeric or other visual feature which isoptically-encoded with information for identification and/or securitypurposes.

In accordance with the present invention, there is provided a substrateor other article having a surface provided with an alpha-numeric featurewhich comprises a plurality of characters, or another visual featurewhich comprises a plurality of elements, at least some of the charactersor elements of said feature being of selected optical states inaccordance with a predetermined code.

It will be appreciated that by selecting the optical states of thecharacters or other elements in accordance with the predetermined code,these characters or other elements can be collectively encoded with anydesired information.

Preferably the differences exhibited by each character or element, inits different states, are substantially imperceptible (or not readilyperceptible) to the naked eye. The different states of each character orelement can however be discriminated by optical character recognitionsystems.

The alpha-numeric feature may comprise any desired information providedon the substrate or other article, for the benefit of the end user ofthe article, and typically comprising a succession of words eachconsisting of one or a series of characters. Alternatively, the visualfeature may comprise a bar-code consisting of a number of parallel barsof different widths and spacings. The present invention enables a largeamount of additional information to be encoded into the alpha-numeric orother visual feature, for the purposes of identification and/or securityagainst counterfeiting of the product. For example, any one or more ofthe following items of information may be encoded into the alpha-numericor other feature: data indicating where the product was manufactured,the date of manufacture, the product name, and the serial number of theproduct.

In a first embodiment, using binary encoding, a character or element ofundistorted shape is regarded as logic state “0”, and the same characteror element of substantially the same shape, but with one or more minoralterations or distortions in shape, as logic state “1”. For example,the state “0” for alpha-numeric characters may be provided by apredetermined font, state “1” being provided by corresponding charactersfrom which one or more small areas are removed or added. The alterationsmay comprise curved or straight-line shapes cut into the edge of thecharacter or other element of the visual feature, or protruding from it,or cut out of the body of the character or other element: preferablysuch shapes are simple geometric shapes such as squares or rectangles.Alternatively, the alterations may consist of alterations in thethickness of one or more of the lines forming each character or otherelement. Preferably these alterations change each time the character orelement is repeated in the alpha-numeric or other visual feature: thus,each character or element has a number of different alterations inshape, each representing state “1”, which may be selected on a randombasis. It may be desirable for each character or element to have anumber of alterations in shape, any of which can be read to indicatestate “1”, to ensure reliable reading. For example, the visual featuremay comprise a bar-code, the elements (i.e. bars) of which are formedwith alterations as described above.

In a second embodiment, alpha-numeric characters are selected from twoalternative fonts, the corresponding characters in the two fonts beingsubstantially the same but exhibiting one or more minor differences inshape.

In a third embodiment, alpha-numeric characters are selected from asingle font, each character in its different states being of identicalshape but different in size or shifted from its nominal position withinits multi-character word (e.g. displaced slightly to the left or right,or up or down, from its nominal position).

In a fourth embodiment, the different states of each character orelement are defined by different shades of colour or differentgreyscales (the differences preferably being imperceptible to the nakedeye), or otherwise different optical responses under incident light. Forexample, in one logic state, the character or element may be arranged toplayback at a different wavelength from the incident light, for exampleby the provision of a pigment (e.g. fluorescent, rare earth oranti-Stokes pigments). The pigment (e.g. an anti-Stokes pigment) may besuch that it plays back in the visible spectrum when illuminated by alonger wavelength laser light. Other pigments or dyes could be usedwhich playback with UV light, or others which fluoresce.

In a fifth embodiment, the visual feature comprises a bar-codeconsisting of a number of parallel bars, the widths and spacings ofwhich differ in accordance with a code, in conventional manner: inaddition, and in accordance with the present invention, some of the barsare shifted (to the right or left or up or down) from their nominalpositions, and/or are modified in length, and/or modified in width (fromnominal widths), in accordance with a predetermined code, impartingadditional information to the feature.

Whilst the above description refers to binary encoding, it will beappreciated that higher orders of encoding may be used. For example,several different states for each character or element may be providedby different alterations in shape, or different combinations of shapealterations, font shapes or sizes or shade differences (or otherdifferences in optical responses) may be employed.

The encoding employed in the alpha-numeric or other feature ispreferably encrypted and preferably includes a checksum and/or errorcorrection.

It will be appreciated that the alpha-numeric or other feature may beprinted on the substrate or other article using any appropriate form ofprinter, including inkjet printers, electrostatic printers and thermaltransfer printers. The printer is preferably computer-controlled suchthat successive printed products, or successive batches of printedproducts, may be encoded differently.

Also, in accordance with the present invention, there is provided anapparatus for applying an alpha-numeric or other visual feature to asurface of a substrate or other article, the apparatus being arranged toapply at least some of the characters or elements of said feature inoptical states selected in accordance with a predetermined code.

Further in accordance with the present invention, there is provided anapparatus for reading an alpha-numeric or other visual feature carriedon a surface of a substrate or other article, at least some of thecharacters or elements of said feature being of optical states selectedin accordance with a predetermined code, the apparatus being arranged todetermine the optical states of said characters or elements anddetermine the information encoded therein.

As a further security measure, the surface of the substrate or otherarticle may carry a security feature such as a hologram or otheroptically variable device. Preferably the security feature incorporatesa security code, and the information encoded into the alpha-numeric orother visual feature includes the same security code. Then in thereading process, the security code is read from the security feature andcompared with the security code decoded from the alpha-numeric or othervisual feature: if these two codes fail to match, the product isregarded as being of suspect authenticity.

The security code may be random. Thus, the security feature may beapplied in a manner such that it incorporates a security code which israndom in nature: the security feature is then examined to read itssecurity code, which is then included in the data to be encoded in thealpha-numeric or other visual feature.

For example, the security feature may be printed onto the substratesurface, the printing ink including particles of pigment which areapplied in a random manner. The security feature, once applied, is thenexamined by machine to plot the positions and/or colours of the pigmentparticles: from this information, the security code is generated.Instead of using particles of pigment for the security feature, magneticor electrically-conductive particles may be used, or chemical or othertagging agents, the positions of which are then determined by machine,to generate the security code.

The security feature is preferably provided in an area separate from thealpha-numeric or other visual feature: it may for example form a logo orother design feature on the substrate surface.

Embodiments of the present invention will now be described by way ofexample only and with reference to the accompanying drawings, in which:

FIG. 1 is a front view of a product label provided with visual featuresin accordance with the present invention;

FIG. 2 shows several characters in their standard and altered shapes;

FIG. 3 shows a character with a number of alterations from its standardshape;

FIG. 4 is a schematic diagram of apparatus for applying a visual featureand a security feature to product labels; and

FIG. 5 is a schematic diagram of an apparatus for reading encodedinformation from visual features of product labels.

Referring to FIG. 1, there is shown a product label L which is printedwith alpha-numeric information 10, consisting of a succession of wordseach made up of one or a series of characters, and also with themanufacturer's logo 12. The alpha-numeric information may be of anydesired content, for the benefit in usual manner of the user of theproduct: the example shown is a label for prescribed medication for aparticular patient. The label is also provided with a machine-readablebar-code 14 made up of a number of parallel bars of different widths andspacings in accordance with a predetermined code. It will be appreciatedthat the characters of the alpha-numeric information 10 normally occupynominal positions at regular intervals, as do the bars of the bar code14.

In accordance with the present invention, at least some of thecharacters of the alpha-numeric information 10 are of selected opticalstates, in accordance with a predetermined code. In particular, in theexample shown, use is made of binary encoding, in which the charactersare selected from a predetermined font without any alteration ordistortion in shape (logic state “0”), or are selected from the samefont but include minor alterations or distortions in shape (logic state“1”). FIG. 2 shows three characters, firstly in their standard orunaltered states (“0”), and secondly in their altered states (“1”): itwill be noted that, in their altered states, the characters have minorsections or areas removed; instead, they could have similar minor areasadded, as protrusions, or other differences in shape e.g. lines ofdifferent curvature or lines of different thickness.

The difference between a character in its state “0” and the samecharacter in its state “1” is minor and not readily perceptible to thenaked eye. However, the different shapes of character can bediscriminated reliably using optical reading devices, for example astandard quality desktop scanner coupled to a computer running opticalcharacter recognition software.

The altered form of each character may change each time it is repeated,within the alpha-numeric feature, to increase the difficulty ofidentifying a pattern. For example, there may be 4 or more altered formsfor each character, chosen preferably in random and each representingstate “1” for that character. Moreover, it may be desirable for eachcharacter, in state “1”, to include a number of alterations to ensurereliable reading and a level of redundancy: FIG. 3 shows a characterwith a number of alterations in shape, some comprising small areasremoved, some comprising small areas added, and some comprising voids orsmall areas removed from within the body of the character (i.e.localised between opposite edges thereof).

In a second embodiment, the characters may be selected from twoalternative fonts, the corresponding characters in the two fonts beingsimilar or identical in shape except for one or more minor differencesin shape, these differences being imperceptible to the naked eye.

In a third embodiment, the characters may be selected from a single fontwith each character selected of slightly different sizes or shifted (tothe right or left or up or down) from its nominal position within itsmulti-character word, the differences in size or position again beingminor and imperceptible to the naked eye.

In a fourth embodiment, each character may be identical in shape andsize, in its states “0” and “1”, but of different colour shades ordifferent greyscales: again, the differences in colour shade areimperceptible to the naked eye. As a further example, and as mentionedpreviously, in one state the character may include a pigment or otheradditive to that it gives a different response under incident light(whether in the visible part of the spectrum or outside).

In a fifth embodiment, some of the bars of the bar-code 14 are shifted(to the right or left or up or down) from their nominal positions withinthe bar-code, and/or some of the bars may be shorter or longer thantheir nominal lengths, and/or narrow or wider than their nominal widths.The amount of the shift in position of each bar, or the modification inlength or width of each bar, is minor and imperceptible to the nakedeye. The shifts in position, or modifications in length or width, are inaccordance with a predetermined code, imparting information to thebar-code which is additional to its normal machine-readable information.Instead, at least some of the bars of the bar-code may be provided withminor alterations or distortions of shape, in accordance withpredetermined code, for example in the form of minor sections removed oradded (e.g. as protrusions).

In each of the above-described embodiments, the present inventionenables a large amount of information to be encoded into thehuman-readable alpha-numeric information 10, for the purposes ofidentification and/or security against product counterfeiting. Inaddition, in the example shown in FIG. 1, the logo 12 is applied in amanner enabling a random security code to be generated from it, and thisrandom security code is further encoded into the alpha-numeric feature10 or bar code 14. For example, the product label L shown in FIG. 1 maybe printed initially with the logo 12 (or an alternative patch or area),the print incorporating particles of pigment, such as rare earthpigments which play back with long wavelength light: a printer 20 forthis purpose is shown in FIG. 4. The pigment particles are accordinglyapplied to the substrate in random manner. Then the substrate, withprinted logo, is examined in a reader 22 (FIG. 4), to plot the positionsof the pigment particles, and optionally their respective playbackcolours, and, using a predetermined algorithm, generate a security codeaccording to the locations of the differently coloured pigmentparticles. This security code is provided as an output CODE S from thereader 22 and then forms part of the data encoded into the alpha-numericfeature 10 or bar code 14: the output CODE S is used by a computer 24controlling a printer 26 which prints the alpha-numeric feature 10and/or bar-code 14.

In subsequently reading the alpha-numeric feature 10 or bar code 14, thelogo 12 (or alternative patch) is also read to regenerate the securitycode from it: this is then compared against the security code read fromthe alpha-numeric feature 10 or bar code 14. FIG. 5 shows a reader 30arranged to read the security feature and determine its security codeCODE S, and also read the alpha-numeric feature 10 and/or bar-code 14and determine both its security CODE F and its encoded information.

Because the pigment particles do not playback visible light except undernon-visible (infra red) light, the security feature cannot be copied bystandard colour-copying equipment: the feature is accordingly secureagainst counterfeit replication.

Instead of using randomly-applied pigments in the logo 12 (oralternative patch), magnetic particles (preferably particles of highmagnetic coercivity) or electrically-conductive particles or fibres, orchemical or other tagging agents may be applied in similar randommanner, and similarly used to generate a random security code forinclusion in the information encoded into the alpha-numeric feature 10or bar code 14. The magnetic particles may be read using a magneticfield, whilst the electrical particles or fibres may be read using anelectric field or a microwave field, and the chemical tagging agents maybe read using chemical or optical exposure.

As a further security option, an optically variable device (such as ahologram) may be applied to the substrate: this device may include asecurity code, which is also included in the information encoded intothe alpha-numeric feature 10 or into the bar code 14.

As a yet further security option, the security patch may be formed byapplying to the substrates, in random manner, discrete dots or otherelements of one or more different sheet materials, e.g. hot stampingfoils (or other foils). The pattern and/or distribution of theseelements of e.g. reflective foil are then read optically, to generatethe random security code, as described above. The pattern of foilelements may form an optically variable device. The discrete dots orelements of sheet material may include magnetic, electrical, chemical orother tagging agents enabling their positions to be machine-read.

1-20 (canceled)
 21. An article, comprising: a surface; a visual featureincluded on said surface; a plurality of elements with at least aportion of elements of said plurality of elements being of selectedoptical states according to a predetermined code, so that said visualfeature is encoded with information; and, a security featureincorporating a security code, said security feature being formed sothat said security code is random, said information being encoded intosaid visual feature includes a code derived from said security featureand corresponding to said security code.
 22. The article according toclaim 21, wherein each element of said portion of elements includes afirst optical state of said selected optical states of a predeterminedshape and a second optical state of said selected optical states havinga substantially similar shape that differs from said predetermined shapeof said first optical state due to a presence of minor alterations. 23.The article according to claim 22, wherein said substantially similarshape of said second optical state differs from said predetermined shapeof said first optical state by the presence of an additional small areain said substantially similar shape.
 24. The article according to claim23, wherein said additional small area is added to an edge of saidelement of said portion of elements.
 25. The article according to claim22, wherein said substantially similar shape of said second opticalstate differs from said predetermined shape of said first optical stateby a removal of a small area in said substantially similar shape ascompared to said predetermined shape.
 26. The article according to claim25, wherein said small area is removed from an edge of said element ofsaid portion of elements.
 27. The article according to claim 25, whereinsaid small area is removed from an area within said element of saidportion of elements.
 28. The article according to claim 22, wherein eachsaid element of said portion of elements includes lines forming saidelement, with said minor alterations being comprised of a change ofthickness of at least one line of said lines forming said element. 29.The article according to claim 28, wherein said change of thickness ofat least one said line of said element is an increase of thickness. 30.The article according to claim 28, wherein said change of thickness ofat least one said line of said element is an decrease of thickness. 31.The article according to claim 22, wherein said elements of said portionof elements comprise alpha-numeric characters selected from twoalternative fonts, each character of said alpha-numeric characters insaid two alternative fonts being substantially identical, except for atleast one difference in shape.
 32. The article according to claim 21,wherein each element of said portion of elements includes a firstselected optical state of said selected optical states of apredetermined size and a second selected optical state of said selectedoptical states of a different size as compared to said predeterminedsize.
 33. The article according to claim 21, wherein said selectedoptical states includes a first selected optical state and a secondoptical state with each element of said portion of elements having saidfirst selected optical state occupying a predetermined nominal positionand said second optical state occupying a position shifted from saidpredetermined nominal position.
 34. The article according to claim 21,wherein said selected optical states includes a first selected opticalstate and a second optical state with each element of said portion ofelements having said first selected optical state of a predeterminedcolor shade or greyscale and said second selected optical state of adifferent color shade or grey as compared to said predetermined colorshade or grey-scale.
 35. The article according to claim 21, wherein saidselected optical states includes a first selected optical state and asecond selected optical state with each element of said portion ofelements having said first optical state comprising a first opticalresponse under incident light and said second selected optical statecomprising a second optical response under said incident light, saidsecond optical response being different from said first opticalresponse.
 36. The article according to claim 35, wherein each saidelement of said portion of elements in said first selected optical stateplays back light at a different wavelength from said incident light. 37.The article according to claim 35, wherein each said element of saidportion of elements in said second selected optical state plays backlight at a different wavelength from said incident light.
 38. Thearticle according to claim 21, wherein said visual feature comprises abar-code having a plurality of parallel bars, some parallel bars of saidplurality of parallel bars being shifted from their nominal positionsaccording to said predetermined code.
 39. The article according to claim21, wherein said visual feature comprises a bar-code having a pluralityof parallel bars, some parallel bars of said plurality of parallel barsbeing modified from their nominal lengths or nominal widths according tosaid predetermined code.
 40. The article according to claim 21, whereindifferences exhibited by each element of said portion of elements insaid selected optical states are substantially imperceptible to aperson's unaided eye.
 41. The article according to claim 21, whereinsaid security feature is provided on an area of said surface separatefrom said visual feature.
 42. The article according to claim 21, whereinsaid security feature comprises a printed feature comprising pigment,magnetic, electrical or chemical particles, or fibers, distributed via arandom application with said random application providing said securitycode, said security code being a random security code.
 43. An article,comprising: a surface; a visual feature included on said surface; and, aplurality of elements defining information with at least a portion ofelements of said plurality of elements being of selected optical statesaccording to a predetermined code, each element of said portion ofelements, in one optical state of said selected optical states, playingback light at a different wavelength from a wavelength of light thereon.44. The article according to claim 43, wherein said elements comprisealpha-numeric characters.
 45. An article, comprising: a surface; avisual feature included on said surface; and, a bar-code including aplurality of parallel bars with at least some parallel bars of saidplurality of parallel bars being shifted from their nominal positionsaccording to a predetermined code.
 46. An article, comprising: asurface; a visual feature included on said surface; and, a bar-codeincluding a plurality of parallel bars with at least some parallel barsof said plurality of parallel bars being modified from their nominallengths or widths according to a predetermined code.
 47. An apparatusfor applying a visual feature to a surface of an article, comprising:means for applying to a surface of an article a plurality of elementsforming a visual feature, at least a portion of elements of saidplurality of elements being of selected optical states according to apredetermined code so that said visual feature is encoded withinformation; and, means for encoding a random security code from asecurity feature contained with said article, said random security codeincluding a corresponding code included within said visual featureencoded with said information.